rename 8253pit.c to timer.c

defs.h

@@ -7,9 +7,6 @@ struct proc;
 struct spinlock;
 struct stat;
 
-// 8253pit.c
-void            pit8253_timerinit(void);
-
 // bio.c
 void            binit(void);
 struct buf*     bread(uint, uint);
@@ -140,6 +137,9 @@ int             fetchint(struct proc*, uint, int*);
 int             fetchstr(struct proc*, uint, char**);
 void            syscall(void);
 
+// timer.c
+void            timer_init(void);
+
 // trap.c
 void            idtinit(void);
 extern int      ticks;

main.c

@@ -46,7 +46,7 @@ main(void)
   ide_init();      // disk
   bootothers();    // boot other CPUs
   if(!ismp)
-    pit8253_timerinit(); // uniprocessor timer
+    timer_init(); // uniprocessor timer
   userinit();      // first user process
 
   // enable interrupts on this processor.
@@ -74,7 +74,7 @@ mpmain(void)
   scheduler();
 }
 
-void
+static void
 bootothers(void)
 {
   extern uchar _binary_bootother_start[], _binary_bootother_size[];

runoff.list

@@ -64,7 +64,7 @@ picirq.c
 kbd.h
 kbd.c
 console.c
-8253pit.c
+timer.c
 
 # user-level
 usys.S

timer.c

@@ -0,0 +1,32 @@
+// Intel 8253/8254/82C54 Programmable Interval Timer (PIT).
+// Only used on uniprocessors;
+// SMP machines use the local APIC timer.
+
+#include "types.h"
+#include "defs.h"
+#include "traps.h"
+#include "x86.h"
+
+#define IO_TIMER1       0x040           // 8253 Timer #1
+
+// Frequency of all three count-down timers;
+// (TIMER_FREQ/freq) is the appropriate count
+// to generate a frequency of freq Hz.
+
+#define TIMER_FREQ      1193182
+#define TIMER_DIV(x)    ((TIMER_FREQ+(x)/2)/(x))
+
+#define TIMER_MODE      (IO_TIMER1 + 3) // timer mode port
+#define TIMER_SEL0      0x00    // select counter 0
+#define TIMER_RATEGEN   0x04    // mode 2, rate generator
+#define TIMER_16BIT     0x30    // r/w counter 16 bits, LSB first
+
+void
+timer_init(void)
+{
+  // Interrupt 100 times/sec.
+  outb(TIMER_MODE, TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT);
+  outb(IO_TIMER1, TIMER_DIV(100) % 256);
+  outb(IO_TIMER1, TIMER_DIV(100) / 256);
+  irq_enable(IRQ_TIMER);
+}